1. Field of the Invention
The invention relates to a broaching machine comprising a machine table receiving the workpiece, a platform, which is driven and displaceable by a drive relative to the machine table, as well as one or a plurality of broaching tools, which can be coupled with the platform and which work in the axial direction. The machine is mounted on a machine frame.
2. The Prior Art
Broaching machines for machining the inside and outside of workpieces, such as for producing grooves, toothings or the like, are known from the printed document "Broaching Machines" published in 1988 by the firm Honnema GmbH, Am Stadtwald B, Wickede. In detail, this broaching machine comprises a vertical arrangement, having a machine frame for a machine table that receives the workpiece horizontally. Below the machine table, there is a platform, which is displaceable via a spindle drive, and which can be coupled with one or more broaching tools in the form of broaching spindles, which grip through the table. In their operating positions, the end side shafts of the relatively long broaching tools are received in a shaft holder on the platform, in a pliers-like manner. The shaft of the broaching tools is adjoined by an insertion section which is adjoined by the actual broaching section supporting the cutters. The other end of the broaching tool may be detachably received in an end-piece holder on the frame of the machine.
Broaching work of this type requires that the broaching tool have a great working length. Therefore, the broaching tool must be displaced through the workpiece and the table via the platform over a long distance. The lift of the platform is therefore extensive, and the machine is required to have a great structural height. This necessarily results in a great operating height for working the workpiece which has to be placed or advanced on the table. These broaching machines therefore have to be equipped with either suitably dimensioned operating pits or operating platforms.
The lengths required for the broaching tools require long spindle drives. However, the spindles of the spindle drive, which are supported on their end-sides, with the platform being mounted on and driven by the spindle drive, permit only limited rotary speeds and thus limit the speed of the platform, because vibration is caused in the spindle drive when a certain speed is exceeded. These vibrations decrease the operating accuracy of the machines.